Host response to translocated microbial products predicts outcomes of patients with HBV or HCV infection

Gut Microbiota in Patients with Non-Alcoholic Fatty Liver Disease without Type 2 Diabetes: Stratified by Body Mass Index

The relationship between gut dysbiosis and body mass index (BMI) in non-diabetic patients with non-alcoholic fatty liver disease (NAFLD) is not adequately characterized. This study aimed to assess gut microbiota's signature in non-diabetic individuals with NAFLD stratified by BMI. The 16S ribosomal RNA sequencing was performed for gut microbiota composition in 100 patients with NAFLD and 16 healthy individuals. The differential abundance of bacterial composition between groups was analyzed using the DESeq2 method. The alpha diversity (Chao1, Shannon, and observed feature) and beta diversity of gut microbiota significantly differed between patients with NAFLD and healthy controls. However, significant differences in their diversities were not observed among subgroups of NAFLD. At the phylum level, there was no trend of an elevated Firmicutes/Bacteroidetes ratio according to BMI. At the genus level, patients with lean NAFLD displayed a significant enrichment of Escherichia-Shigella and the depletion of Lachnospira and Subdoligranulum compared to the non-lean subgroups. Combining these bacterial genera could discriminate lean from non-lean NAFLD with high diagnostic accuracy (AUC of 0.82). Non-diabetic patients with lean NAFLD had a significant difference in bacterial composition compared to non-lean individuals. Our results might provide evidence of gut microbiota signatures associated with the pathophysiology and potential targeting therapy in patients with lean NAFLD.

HIV-Infected Hepatic Stellate Cells or HCV-Infected Hepatocytes Are Unable to Promote Latency Reversal among HIV-Infected Mononuclear Cells

Due to a common mode of transmission through infected human blood, hepatitis C virus (HCV) and human immunodeficiency virus (HIV) co-infection is relatively prevalent. In alignment with this, HCV co-infection is associated with an increased size of the HIV reservoir in highly active antiretroviral therapy (HAART)-treated individuals. Hence, it is crucial to comprehend the physiological mechanisms governing the latency and reactivation of HIV in reservoirs. Consequently, our study delves into the interplay between HCV/HIV co-infection in liver cells and its impact on the modulation of HIV latency. We utilized the latently infected monocytic cell line (U1) and the latently infected T-cell line (J-Lat) and found that mediators produced by the infection of hepatic stellate cells and hepatocytes with HIV and HCV, respectively, were incapable of inducing latency reversal under the studied conditions. This may favor the maintenance of the HIV reservoir size among latently infected mononuclear cells in the liver. Further investigations are essential to elucidate the role of the interaction between liver cells in regulating HIV latency and/or reactivation, providing a physiologically relevant model for comprehending reservoir microenvironments in vivo.

Contributing roles of mitochondrial dysfunction and hepatocyte apoptosis in liver diseases through oxidative stress, post-translational modifications, inflammation, and intestinal barrier dysfunction

This review provides an update on recent findings from basic, translational, and clinical studies on the molecular mechanisms of mitochondrial dysfunction and apoptosis of hepatocytes in multiple liver diseases, including but not limited to alcohol-associated liver disease (ALD), metabolic dysfunction-associated steatotic liver disease (MASLD), and drug-induced liver injury (DILI). While the ethanol-inducible cytochrome P450-2E1 (CYP2E1) is mainly responsible for oxidizing binge alcohol via the microsomal ethanol oxidizing system, it is also responsible for metabolizing many xenobiotics, including pollutants, chemicals, drugs, and specific diets abundant in n-6 fatty acids, into toxic metabolites in many organs, including the liver, causing pathological insults through organelles such as mitochondria and endoplasmic reticula. Oxidative imbalances (oxidative stress) in mitochondria promote the covalent modifications of lipids, proteins, and nucleic acids through enzymatic and non-enzymatic mechanisms. Excessive changes stimulate various post-translational modifications (PTMs) of mitochondrial proteins, transcription factors, and histones. Increased PTMs of mitochondrial proteins inactivate many enzymes involved in the reduction of oxidative species, fatty acid metabolism, and mitophagy pathways, leading to mitochondrial dysfunction, energy depletion, and apoptosis. Unique from other organelles, mitochondria control many signaling cascades involved in bioenergetics (fat metabolism), inflammation, and apoptosis/necrosis of hepatocytes. When mitochondrial homeostasis is shifted, these pathways become altered or shut down, likely contributing to the death of hepatocytes with activation of inflammation and hepatic stellate cells, causing liver fibrosis and cirrhosis. This review will encapsulate how mitochondrial dysfunction contributes to hepatocyte apoptosis in several types of liver diseases in order to provide recommendations for targeted therapeutics.

Organism profile and C-reactive protein (CRP) response are different in periprosthetic joint infection in patients with hepatitis

PURPOSE

Hepatitis B and C are important and relatively common health issues. It is known that many patients who underwent total knee and hip arthroplasty were also diagnosed with hepatitis. These patients are at higher risk of periprosthetic joint infection (PJI). This study aimed to investigate the differences in PJI cases in hepatitis B and C patients.

METHODS

This is a retrospective case-controlled single-center study. A total of 270 patients with hepatitis and non-hepatitis (control group) who underwent one-stage septic exchange to the hip and knee joints were included in the study. All patients' previous surgical histories, infective organisms, C-reactive protein (CRP) values before septic exchange, and demographic data were evaluated. All microbiological and laboratory evaluations were performed separately for knee and hip arthroplasty.

RESULTS

The mean CRP levels of Hep B- and C-positive patients, who underwent one-stage septic exchange in the knee joint, were 23.6 mg/L. In the control group, this value was 43.1 mg/L and a statistically significant difference was found between the groups (p = 0.004). Gram-negative organisms were identified in a larger proportion of patients with hepatitis who developed PJI in both hip and knee joints and underwent one-stage septic exchange (p = 0.041/p = 0.044).

CONCLUSION

PJIs caused by Gram-negative bacteria are encountered more frequently in patients with hepatitis than in the control group. In addition, the CRP rise is less in patients with hepatitis compared to PJI cases in the control group. Patient-specific evaluation is required in cases of PJI in patient groups with co-existing hepatitis.

A gut microbiome signature for HIV and metabolic dysfunction-associated steatotic liver disease

Introduction

Metabolic dysfunction-associated steatotic liver disease (MASLD), has emerged as an increasingly recognized problem among people living with HIV (PLWH). The gut-liver axis is considered to be strongly implicated in the pathogenesis of MASLD. We aimed to characterize the gut microbiota composition in PLWH and MASLD and compare it with that of two control groups: PLWH without MASLD and individuals with MASLD without HIV infection.

Methods

We collected clinical data and stool samples from participants. Bacterial 16S rRNA genes were amplified, sequenced, and clustered into operational taxonomic unit. Alpha diversity was studied by Shannon and Simpson indexes. To study how different the gut microbiota composition is between the different groups, beta diversity estimation was evaluated by principal coordinate analysis (PCoA) using Bray-Curtis dissimilarity. To further analyze differences in microbiome composition we performed a linear discriminant analysis (LDA) effect size (LEfSe).

Results

We included 30 HIV+MASLD+, 30 HIV+MASLD- and 20 HIV-MASLD+ participants. Major butyrate producers, including Faecalibacterium, Ruminococcus, and Lachnospira dominated the microbiota in all three groups. Shannon's and Simpson's diversity metrics were higher among MASLD+ individuals (Kruskal-Wallis p = 0.047). Beta diversity analysis showed distinct clustering in MASLD-, with MASLD+ participants overlapping regardless of HIV status (ADONIS significance <0.001). MASLD was associated with increased homogeneity across individuals, in contrast to that observed in the HIV+NAFDL- group, in which the dispersion was higher (Permanova test, p value <0.001; ANOSIM, p value <0.001). MASLD but not HIV determined a different microbiota structure (HIV+MASLD- vs. HIV+MASLD+, q-value = 0.002; HIV-MASLD+ vs. HIV+MASLD+, q-value = 0.930; and HIV-MASLD+ vs. HIV+MASLD-, q-value < 0.001). The most abundant genera in MASLD- were Prevotella, Bacteroides, Dialister, Acidaminococcos, Alloprevotella, and Catenibacterium. In contrast, the most enriched genera in MASLD+ were Ruminococcus, Streptococcus, Holdemanella, Blautia, and Lactobacillus.

Conclusions

We found a microbiome signature linked to MASLD, which had a greater influence on the overall structure of the gut microbiota than HIV status alone.

Gut Microbiota and Bacterial Translocation in the Pathogenesis of Liver Fibrosis

Cirrhosis is the end result of liver fibrosis in chronic liver diseases. Studying the mechanisms of its development and developing measures to slow down and regress it based on this knowledge seem to be important tasks for medicine. Currently, disorders of the gut-liver axis have great importance in the pathogenesis of cirrhosis. However, gut dysbiosis, which manifests as increased proportions in the gut microbiota of Bacilli and Proteobacteria that are capable of bacterial translocation and a decreased proportion of Clostridia that strengthen the intestinal barrier, occurs even at the pre-cirrhotic stage of chronic liver disease. This leads to the development of bacterial translocation, a process by which those microbes enter the blood of the portal vein and then the liver tissue, where they activate Kupffer cells through Toll-like receptor 4. In response, the Kupffer cells produce profibrogenic cytokines, which activate hepatic stellate cells, stimulating their transformation into myofibroblasts that produce collagen and other elements of the extracellular matrix. Blocking bacterial translocation with antibiotics, probiotics, synbiotics, and other methods could slow down the progression of liver fibrosis. This was shown in a number of animal models but requires further verification in long-term randomized controlled trials with humans.

Investigating the Association Between Diet-Induced "Leaky Gut" and the Development of Prediabetes

INTRODUCTION

Chronic consumption of a high-calorie diet compromises the gut microbiota and the integrity of the intestinal wall, which causes translocation of bacterial lipopolysaccharides (LPS) into the blood. This elicits the secretion of pro-inflammatory cytokines, resulting in inflammation. However, how a high-fat high carbohydrate diet affects intestinal permeability and its possible role in the development of prediabetes have not been investigated. This study investigated the effects of HFHC diet-induced prediabetes on gut microbiota and intestinal permeability in male Sprague Dawley rats.

METHODS

The animals were randomly assigned into the non-prediabetic (NPD) and diet-induced prediabetic (PD) groups (n=6) for 20 weeks. Then, the fecal samples were analyzed to measure the gut microbiota level of Firmicutes, Bacteroidetes, and Proteobacteria in both animal groups. Blood glucose, plasma insulin, serum zonulin, plasma LPS, soluble CD14, tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), C-reactive protein (CRP), and intestinal fatty-acid binding protein (IFABP) concentrations were measured.

RESULTS

The PD group had a reduction in the Firmicutes and an increase in Bacteroidetes and Proteobacteria levels compared to those in the NPD group. Blood glucose, insulin concentration, serum zonulin, and plasma sCD14 concentrations in the PD group increased significantly, while plasma LPS concentrations were similar to the NPD group. Concentrations of plasma TNF-α, IL-6, CRP, and IFABP, an intracellular protein expressed in the intestine, increased in PD compared to the NPD group.

CONCLUSIONS

the study results cumulatively suggest that chronic consumption of the HFHC diet may be associated with the dysregulation of gut microbiota, leading to increased intestinal permeability.

Exploring Plasma-Level Gut Microbiota Mediators and Pro-Inflammatory Markers in Pregnant Women with Short Cervix and Gestational Diabetes Mellitus

The composition of the gut microbiota (GM) undergoes significant changes during pregnancy, influenced by metabolic status, energy homeostasis, fat storage, and hormonal and immunological modifications. Moreover, dysbiosis during pregnancy has been associated with preterm birth, which is influenced by factors such as cervical shortening, infection, inflammation, and oxidative stress. However, dysbiosis also affects the levels of lipopolysaccharide-binding protein (LBP), short-chain fatty acids (SCFAs), and free fatty acids (FFA) in other tissues and the bloodstream. In this study, we investigated the plasmatic levels of some pro-inflammatory cytokines, such as matrix metalloproteinases-8 (MMP-8), interleukin-8 (IL-8), heat shock protein 70 (Hsp70), and microbial markers in pregnant women with a short cervix (≤25 mm) compared to those with normal cervical length (>25 mm). We examined the differences in the concentration of these markers between the two groups, also assessing the impact of gestational diabetes mellitus. Understanding the relationship between GM dysbiosis, inflammatory mediators, and cervical changes during pregnancy may contribute to the identification of potential biomarkers and therapeutic targets for the prevention and management of adverse pregnancy outcomes, including preterm birth.

Long-term benefit of DAAs on gut dysbiosis and microbial translocation in HCV-infected patients with and without HIV coinfection

Long-term effect of Direct-acting antivirals (DAAs) on gut microbiota, short-chain fatty acids (SCFAs) and microbial translocation in patients with hepatitis C virus (HCV) infection who achieve sustained virological response (SVR) were limited. A longitudinal study of 50 patients with HCV monoinfection and 19 patients with HCV/HIV coinfection received DAAs were conducted. Fecal specimens collected at baseline and at week 72 after treatment completion (FUw72) were analyzed for 16S rRNA sequencing and the butyryl-CoA:acetateCoA transferase (BCoAT) gene expression using real-time PCR. Plasma lipopolysaccharide binding protein (LBP) and intestinal fatty acid binding protein (I-FABP) were quantified by ELISA assays. SVR rates in mono- and coinfected patients were comparable (94% vs. 100%). The improvement of gut dysbiosis and microbial translocation was found in responders but was not in non-responders. Among responders, significant restoration of alpha-diversity, BCoAT and LBP were observed in HCV patients with low-grade fibrosis (F0-F1), while HCV/HIV patients exhibited partial improvement at FUw72. I-FABP did not decline significantly in responders. Treatment induced microbiota changes with increasing abundance of SCFAs-producing bacteria, including Blautia, Fusicatenibacter, Subdoligranulum and Bifidobacterium. In conclusion, long-term effect of DAAs impacted the restoration of gut dysbiosis and microbial translocation. However, early initiation of DAAs required for an alteration of gut microbiota, enhanced SCFAs-producing bacteria, and could reduce HCV-related complications.

Endotoxemia Associated with Liver Disease Correlates with Systemic Inflammation and T Cell Exhaustion in Hepatitis C Virus Infection

Both acute and chronic hepatitis C virus (HCV) infections are characterized by inflammation. HCV and reduced liver blood filtration contribute to inflammation; however, the mechanisms of systemic immune activation and dysfunction as a result of HCV infection are not clear. We measured circulating inflammatory mediators (IL-6, IP10, sCD163, sCD14), indices of endotoxemia (EndoCab, LBP, FABP), and T cell markers of exhaustion and senescence (PD-1, TIGIT, CD57, KLRG-1) in HCV-infected participants, and followed a small cohort after direct-acting anti-viral therapy. IL-6, IP10, Endocab, LBP, and FABP were elevated in HCV participants, as were T cell co-expression of exhaustion and senescence markers. We found positive associations between IL-6, IP10, EndoCab, LBP, and co-expression of T cell markers of exhaustion and senescence. We also found numerous associations between reduced liver function, as measured by plasma albumin levels, and T cell exhaustion/senescence, inflammation, and endotoxemia. We found positive associations between liver stiffness (TE score) and plasma levels of IL-6, IP10, and LBP. Lastly, plasma IP10 and the proportion of CD8 T cells co-expressing PD-1 and CD57 decreased after initiation of direct-acting anti-viral therapy. Although associations do not prove causality, our results support the model that translocation of microbial products, resulting from decreased liver blood filtration, during HCV infection drives chronic inflammation that results in T cell exhaustion/senescence and contributes to systemic immune dysfunction.

Biomarkers of gut barrier dysfunction and risk of hepatocellular carcinoma in the REVEAL-HBV and REVEAL-HCV cohort studies

Gut barrier dysfunction can result in the liver being exposed to an elevated level of gut-derived bacterial products via portal circulation. Growing evidence suggests that systemic exposure to these bacterial products promotes liver diseases including hepatitis, cirrhosis, and hepatocellular carcinoma (HCC). However, prospective studies have not examined the association between biomarkers of gut barrier dysfunction and HCC risk in a population of hepatitis B or C viral (HBV/HCV) carriers. We investigated whether prediagnostic, circulating biomarkers of gut barrier dysfunction were associated with HCC risk, using the Risk Evaluation of Viral Load Elevation and Associated Liver Disease/Cancer (REVEAL)-HBV and REVEAL-HCV cohorts from Taiwan. REVEAL-HBV included 185 cases and 161 matched controls, and REVEAL-HCV 96 cases and 96 matched controls. The biomarkers quantitated were immunoglobulin A (IgA), IgG, and IgM against lipopolysaccharide (LPS) and flagellin, soluble CD14 (an LPS coreceptor), and LPS-binding protein (LBP). Odds ratios (ORs) and 95% confidence intervals (CIs) for associations between biomarker levels and HCC were calculated using multivariable-adjusted logistic regression. A doubling of the circulating levels of antiflagellin IgA or LBP was associated with a 76% to 93% increased risk of HBV-related HCC (OR per one unit change in log2 antiflagellin IgA = 1.76, 95% CI: 1.06-2.93; OR for LBP = 1.93, 95% CI: 1.10-3.38). None of the other markers were associated with an increased risk of HBV-related or HCV-related HCC. Results were similar when cases diagnosed in the first 5 years of follow-up were excluded. Our findings contribute to understanding the interplay of gut barrier dysfunction and primary liver cancer etiology.

Gut-liver axis: barriers and functional circuits

The gut and the liver are characterized by mutual interactions between both organs, the microbiome, diet and other environmental factors. The sum of these interactions is conceptualized as the gut-liver axis. In this Review we discuss the gut-liver axis, concentrating on the barriers formed by the enterohepatic tissues to restrict gut-derived microorganisms, microbial stimuli and dietary constituents. In addition, we discuss the establishment of barriers in the gut and liver during development and their cooperative function in the adult host. We detail the interplay between microbial and dietary metabolites, the intestinal epithelium, vascular endothelium, the immune system and the various host soluble factors, and how this interplay establishes a homeostatic balance in the healthy gut and liver. Finally, we highlight how this balance is disrupted in diseases of the gut and liver, outline the existing therapeutics and describe the cutting-edge discoveries that could lead to the development of novel treatment approaches.

Pro-fibrogenic role of alarmin high mobility group box 1 in HIV-hepatitis B virus coinfection

OBJECTIVE

Liver disease is accelerated in people with HIV (PWH) with hepatitis B virus (HBV) coinfection. We hypothesized that liver fibrosis in HIV-HBV is triggered by increased hepatocyte apoptosis, microbial translocation and/or HIV/HBV viral products.

DESIGN

Sera from PWH with HBV coinfection versus from those with HBV only or putative mediators were used to examine the pathogenesis of liver disease in HIV-HBV.

METHODS

We applied sera from PWH and HBV coinfection versus HBV alone, or putative mediators (including HMGB1), to primary human hepatic stellate cells (hHSC) and examined pro-fibrogenic changes at the single cell level using flow cytometry. High mobility group box 1 (HMGB1) levels in the applied sera were assessed according to donor fibrosis stage.

RESULTS

Quantitative flow cytometric assessment of pro-fibrogenic and inflammatory changes at the single cell level revealed an enhanced capacity for sera from PWH with HBV coinfection to activate hHSC. This effect was recapitulated by lipopolysaccharide, HIV-gp120, hepatocyte conditioned-media and the alarmin HMGB1. Induction of hepatocyte cell death increased their pro-fibrogenic potential, an effect blocked by HMGB1 antagonist glycyrrhizic acid. Consistent with a role for this alarmin, HMGB1 levels were elevated in sera from PWH and hepatitis B coinfection compared to HBV alone and higher in those with HIV-HBV with liver fibrosis compared to those without.

CONCLUSIONS

Sera from PWH and HBV coinfection have an enhanced capacity to activate primary hHSC. We identified an increase in circulating HMGB1 which, in addition to HIV-gp120 and translocated microbial products, drove pro-fibrogenic changes in hHSC, as mechanisms contributing to accelerated liver disease in HIV-HBV.

Effects of direct anti-viral agents on the gut microbiota in patients with chronic hepatitis C

BACKGROUND/PURPOSE

Gut microbiology is associated with liver disease due to gut-liver circulation via the gut microbial-liver axis. There is a paucity of data regarding the effects of treatment to cure hepatitis C virus (HCV) infection on the gut microbiota. The aim of this study was to evaluate the fecal microbiota before and after treatment with direct antiviral agents (DAA) in patients with HCV infection.

METHODS

This prospective study was conducted at Kaohsiung Chung-Gung Memorial Hospital, Taiwan, between December 2019 and November 2020. We recruited patients with chronic hepatitis C (CHC) receiving DAA treatment. Fecal samples were collected twice: at baseline (before DAA treatment; CHC group) and 24 weeks after the end of treatment (EOT; SVR24 group), and once from healthy controls at baseline (control group). The taxonomic composition of the gut microbiota was determined using 16 S ribosomal RNA gene sequencing of stool samples.

RESULTS

A total of 60 patients with CHC and 60 healthy controls matched by age and gender were enrolled. All patients achieved a sustained virologic response (SVR). Alpha diversity was not significantly difference between any groups. Analysis of similarities (ANOSIM) revealed minor differences in the microbial community structure between the control group and CHC group (R = 0.0146, P = 0.098) and less significant differences between the CHC group and SVR24 group (R = -0.0139; P = 0.94). Three phyla and eight genera were differentially abundant between the control group and CHC group.

CONCLUSION

Individuals with CHC do not exhibit significant gut microbiota alterations and eradication of HCV by DAA is not associated with significant modification of the gut microbiota.

Association between probiotic therapy and the risk of hepatocellular carcinoma in patients with hepatitis B-related cirrhosis

Objective

Probiotics may offer cancer-prevention benefits, based on experimental investigation results. This study aimed to determine the potential association between probiotics and hepatocellular carcinoma (HCC) in patients with hepatitis B-related cirrhosis (HBC) receiving antiviral therapy.

Design

This retrospective study included 1267 patients with HBC treated with entecavir or tenofovir between January 2013 and December 2017. The risk of developing HCC was compared between two cohorts of 449 probiotic users (taking a cumulative defined daily doses [cDDD] of ≥ 28) and 818 non-probiotic users (< 28 cDDD). To eliminate the bias caused by confounding factors, propensity score matching (PSM) was used.

Results

On multivariate regression analysis, probiotic consumption was an independent protective factor for HCC occurrence. After PSM, the incidence of HCC was significantly lower in the probiotic users than that in the nonusers (adjusted hazard ratio [aHR]: 0.70, 95% confidence interval: 0.59-0.83, P < 0.001). The aHRs for probiotics with 28-89, 90-180, and >180 cDDD were 0.58, 0.28, and 0.12, respectively, indicating a dose-response pattern. In 28-89, 90-180, and >180 cDDD, the 3-year cumulative incidence of HCC was 8.7%, 4.7%, and 3.0%, respectively. A multivariate stratified analysis confirmed that the administration of probiotics could help patients.

Conclusion

Adjuvant probiotic therapy may reduce the risk of HCC in patients receiving antiviral medication for HBC. However, further clinical research is required to confirm these findings.

Mucosal-Associated Invariant T Cells in the Digestive System: Defender or Destroyer?

Mucosal-associated invariant T (MAIT) cells are a subset of innate T lymphocytes that express the semi-invariant T cell receptor and recognize riboflavin metabolites via the major histocompatibility complex class I-related protein. Given the abundance of MAIT cells in the human body, their role in human diseases has been increasingly studied in recent years. MAIT cells may serve as targets for clinical therapy. Specifically, this review discusses how MAIT cells are altered in gastric, esophageal, intestinal, and hepatobiliary diseases and describes their protective or pathogenic roles. A greater understanding of MAIT cells will provide a more favorable therapeutic approach for digestive diseases in the clinical field.

Evaluation of galectin-3 and intestinal fatty acid binding protein as serum biomarkers in autosomal recessive polycystic kidney disease

BACKGROUND

Autosomal recessive polycystic kidney disease (ARPKD) causes fibrocystic kidney disease, congenital hepatic fibrosis, and portal hypertension. Serum galectin-3 (Gal-3) and intestinal fatty acid binding protein (I-FABP) are potential biomarkers of kidney fibrosis and portal hypertension, respectively. We examined whether serum Gal-3 associates with kidney disease severity and serum I-FABP associates with liver disease severity in ARPKD.

METHODS

Cross-sectional study of 29 participants with ARPKD (0.2-21 years old) and presence of native kidneys (Gal-3 analyses, n = 18) and/or native livers (I-FABP analyses, n = 21). Serum Gal-3 and I-FABP were analyzed using enzyme linked immunosorbent assay. Kidney disease severity variables included estimated glomerular filtration rate (eGFR) and height-adjusted total kidney volume (htTKV). Liver disease severity was characterized using ultrasound elastography to measure liver fibrosis, and spleen length and platelet count as markers of portal hypertension. Simple and multivariable linear regression examined associations between Gal-3 and kidney disease severity (adjusted for liver disease severity) and between I-FABP and liver disease severity (adjusted for eGFR).

RESULTS

Serum Gal-3 was negatively associated with eGFR; 1 standard deviation (SD) lower eGFR was associated with 0.795 SD higher Gal-3 level (95% CI - 1.116, - 0.473; p < 0.001). This association remained significant when adjusted for liver disease severity. Serum Gal-3 was not associated with htTKV in adjusted analyses. Overall I-FABP levels were elevated, but there were no linear associations between I-FABP and liver disease severity in unadjusted or adjusted models.

CONCLUSIONS

Serum Gal-3 is associated with eGFR in ARPKD, suggesting its value as a possible novel biomarker of kidney disease severity. We found no associations between serum I-FABP and ARPKD liver disease severity despite overall elevated I-FABP levels.

Non-alcoholic fatty liver disease is not independently associated with Helicobacter pylori in a central European screening cohort

BACKGROUND

The association between Helicobacter pylori (Hp) infection and non-alcoholic fatty liver disease (NAFLD) is subject of a contentious debate. Data mainly stem from Asian cohorts whereas European data are scarce. We, therefore, investigated an Austrian colorectal cancer screening cohort for an association between Hp and NAFLD.

METHODS

In total, 5338 consecutive participants undergoing screening colonoscopy at a single center in Austria were evaluated in this cross-sectional study. The primary risk factor was being Hp negative or positive. The primary endpoint was the presence of NAFLD defined by ultrasound (NAFLD; primary endpoint). Uni- and multivariable logistic regression models were fitted to obtain odds ratios (OR) and 95% confidence intervals (95%CI). Finally, this association was analyzed in a subgroup of 1128 patients in whom NAFLD was diagnosed by transient elastography (TE, secondary endpoint).

RESULTS

NAFLD prevalence defined by ultrasound did not differ between Hp positive (48%) and negative patients (45%, P=0.097). Accordingly, in uni- (OR 1.12 95% CI 0.98-1.29; P=0.098) and multivariable analysis adjusting for different risk factors (aOR 0.96 95%CI 0.82-1.13; P=0.601) no independent association was found. On subgroup analysis, NAFLD diagnosed by TE was more prevalent in the Hp positive compared to the Hp negative group (49% vs. 38%, P=0.004) and these patients also had higher steatosis grades. However, after adjustment for risk factors, no independent association between Hp positivity and NAFLD diagnosed by TE (aOR 1.26 95%CI 0.89-1.78; P=0.194) was confirmed.

CONCLUSIONS

In this Central European cohort, Hp-positivity was not associated with the diagnosis of NAFLD. Although Hp positive patients seem to be more likely to have a concomitant NAFLD diagnosis, this association might rather relate to a cardiometabolic risk phenotype than causality.

The Impacts of Iron Overload and Ferroptosis on Intestinal Mucosal Homeostasis and Inflammation

Intestinal homeostasis is maintained through the interplay of the intestinal mucosa, local and systemic immune factors, and the microbial content of the gut. Iron is a trace mineral in most organisms, including humans, which is essential for growth, systemic metabolism and immune response. Paradoxically, excessive iron intake and/or high iron status can be detrimental to iron metabolism in the intestine and lead to iron overload and ferroptosis-programmed cell death mediated by iron-dependent lipid peroxidation within cell membranes, which contributes to several intestinal diseases. In this review, we comprehensively review recent findings on the impacts of iron overload and ferroptosis on intestinal mucosal homeostasis and inflammation and then present the progress of iron overload and ferroptosis-targeting therapy in intestinal diseases. Understanding the involved mechanisms can provide a new understanding of intestinal disease pathogenesis and facilitate advanced preventive and therapeutic strategies for intestinal dysfunction and diseases.

A roadmap for serum biomarkers for hepatitis B virus: current status and future outlook

Globally, 296 million people are infected with hepatitis B virus (HBV), and approximately one million people die annually from HBV-related causes, including liver cancer. Although there is a preventative vaccine and antiviral therapies suppressing HBV replication, there is no cure. Intensive efforts are under way to develop curative HBV therapies. Currently, only a few biomarkers are available for monitoring or predicting HBV disease progression and treatment response. As new therapies become available, new biomarkers to monitor viral and host responses are urgently needed. In October 2020, the International Coalition to Eliminate Hepatitis B Virus (ICE-HBV) held a virtual and interactive workshop on HBV biomarkers endorsed by the International HBV Meeting. Various stakeholders from academia, clinical practice and the pharmaceutical industry, with complementary expertise, presented and participated in panel discussions. The clinical utility of both classic and emerging viral and immunological serum biomarkers with respect to the course of infection, disease progression, and response to current and emerging treatments was appraised. The latest advances were discussed, and knowledge gaps in understanding and interpretation of HBV biomarkers were identified. This Roadmap summarizes the strengths, weaknesses, opportunities and challenges of HBV biomarkers.

Plasticity of monocytes and macrophages in cirrhosis of the liver

Cirrhosis of the liver is a systemic condition with raising prevalence worldwide. Patients with cirrhosis are highly susceptible to develop bacterial infections leading to acute decompensation and acute-on-chronic liver failure both associated with a high morbidity and mortality and sparse therapeutic options other than transplantation. Mononuclear phagocytes play a central role in innate immune responses and represent a first line of defence against pathogens. Their function includes phagocytosis, killing of bacteria, antigen presentation, cytokine production as well as recruitment and activation of immune effector cells. Liver injury and development of cirrhosis induces activation of liver resident Kupffer cells and recruitment of monocytes to the liver. Damage- and pathogen-associated molecular patterns promote systemic inflammation which involves multiple compartments besides the liver, such as the circulation, gut, peritoneal cavity and others. The function of circulating monocytes and tissue macrophages is severely impaired and worsens along with cirrhosis progression. The underlying mechanisms are complex and incompletely understood. Recent 'omics' technologies help to transform our understanding of cellular diversity and function in health and disease. In this review we point out the current state of knowledge on phenotypical and functional changes of monocytes and macrophages during cirrhosis evolution in different compartments and their role in disease progression. We also discuss the value of potential prognostic markers for cirrhosis-associated immuneparesis, and future immunotherapeutic strategies that may reduce the need for transplantation and death.

Different profiles of neurocognitive impairment in patients with hepatitis B and C virus infections

The direct impact of chronic hepatitis B and hepatitis C on neurocognition remains elusive due to the frequent comorbidities, and the domains of the neurocognitive functions affected have rarely been investigated comprehensively. We cross-sectionally assessed the neurocognitive functions of the individuals with chronic hepatitis B, chronic hepatitis C, treated chronic hepatitis C with a sustained virologic response, and their healthy control counterparts. Laboratory examinations were used to investigate the impact of inflammation on neurocognition, exclude the medical conditions that could interfere with neurocognition assessment, and assess liver function and fibrotic severity of the liver of the participants. This study found the detrimental impact of chronic hepatitis B on language and executive functions. In contrast, individuals with chronic hepatitis C showed deficits in executive functions, psychomotor speed, memory, and attention. Successful elimination of hepatitis C resulted in improved liver function, but not neuropsychological test performance. Moreover, erythrocyte sedimentation rate level was found to mediate the deficits in the attention of individuals with chronic hepatitis C. These results demonstrate the neurocognitive deficits and the difference in the profiles of neurocognitive deficits in individuals with chronic hepatitis B and chronic hepatitis C. Our study also provided results suggesting the mediation by systemic inflammation on the attention deficit in individuals with chronic hepatitis C.

Heightened microbial translocation is a prognostic biomarker of recurrent tuberculosis

BACKGROUND

Microbial translocation is a known characteristic of pulmonary tuberculosis (PTB). Whether microbial translocation is also a biomarker of recurrence in PTB is not known.

METHODS

We examined the presence of microbial translocation in a cohort of newly diagnosed, sputum smear and culture positive individuals with drug-sensitive PTB. Participants were followed up for a year following the end of anti-tuberculosis treatment. They were classified as cases (in the event of recurrence, n=30) and compared to age and gender matched controls (in the event of successful, recurrence free cure; n=51). Plasma samples were used to measure the circulating microbial translocation markers. All the enrolled study participants were treatment naïve, HIV negative and with or without diabetes mellitus.

RESULTS

Baseline levels of lipopolysaccharide (LPS) (p=0.0002), sCD14 (p=0.0191) and LPS-binding protein (LBP) (p<0.0001) were significantly higher in recurrence than controls and were associated with increased risk for recurrence, while Intestinal fatty acid binding protein (I-FABP) and Endocab showed no association. ROC curve analysis demonstrated the utility of these individual microbial markers in discriminating recurrence from cure with high sensitivity, specificity and AUC.

CONCLUSION

Recurrence following microbiological cure in PTB is characterized by heightened baseline microbial translocation. These markers can be used as a rapid prognostic tool for predicting recurrence in PTB.

The Intestinal Barrier and Its Dysfunction in Patients with Metabolic Diseases and Non-Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) represents an increasing cause of liver disease worldwide, mirroring the epidemics of obesity and metabolic syndrome. As there are still no licensed medications for treating the disease, there is an ongoing effort to elucidate the pathophysiology and to discover new treatment pathways. An increasing body of evidence has demonstrated a crosstalk between the gut and the liver, which plays a crucial role in the development and progression of liver disease. Among other intestinal factors, gut permeability represents an interesting factor at the interface of the gut–liver axis. In this narrative review, we summarise the evidence from human studies showing the association between increased gut permeability and NAFLD, as well as with type-2 diabetes and obesity. We also discuss the manipulation of the gut permeability as a potential therapeutical target in patients with NAFLD.

Calprotectin in viral systemic infections-COVID-19 versus hepatitis C virus

This study aims to evaluate differences in serum and fecal calprotectin in patients with HCV chronic hepatitis and COVID-19 infection and compare them to a control group. This observational study was performed between April 2020 and October 2020 in a single Internal Medicine center. We determined serum and fecal calprotectin, as well as levels of transaminases, C-reactive protein, ferritin, in 25 patients with COVID-19 infection, 30 patients with active HCV chronic infection and 38 patients with cured HCV infection. Serum levels of ALT, AST, C-reactive protein and ferritin were significantly higher in patients with COVID-19 infection (mean values of 127 IU/mL, 135 IU/mL, 123 mg/L and 1034 ng/mL, respectively) than in patients with active HCV infection (mean values of 68 IU/mL, 51 IU/mL, 17 mg/L and 528 ng/mL, respectively) or in patients with cured HCV infection (37 IU/mL, 29 IU/mL, 3.4 mg/L and 274 ng/mL, respectively). Also, serum and fecal calprotectin had increased concentrations in patients with COVID-19 (7.3 µg/mL and 394 µg/mg) versus patients with active hepatitis (2.4 µg/mL and 217 µg/mg) and patients with cured hepatitis (1.2 µg/mL and 38 µg/mg). Values were significantly higher in patients with digestive symptoms related to COVID-19. Serum and fecal calprotectin can be used as inflammatory markers in patients with active viral infections. In COVID-19, calprotectin concentrations can be correlated to the severity of disease, particularly in patients with digestive symptoms.

SPAK Deficiency Attenuates Chemotherapy-Induced Intestinal Mucositis

Introduction

Ste20-related protein proline/alanine-rich kinase (SPAK) affects cell proliferation, differentiation, and transformation, and sodium and chloride transport in the gut. However, its role in gut injury pathogenesis is unclear.

Objective

We determined the role of SPAK in chemotherapy-induced intestinal mucositis using in vivo and in vitro models.

Methods

Using SPAK-knockout (KO) mice, we evaluated the severity of intestinal mucositis induced by 5-fluorouracil (5-FU) by assessing body weight loss, histological changes in the intestinal mucosa, length of villi in the small intestine, pro-inflammatory cytokine levels, proliferative indices, and apoptotic indices. We also evaluated changes in gut permeability and tight junction-associated protein expression. Changes in cell permeability, proliferation, and apoptosis were assessed in SPAK siRNA-transfected 5FU-treated IEC-6 cells.

Results

5-FU-treated SPAK-KO mice exhibited milder intestinal mucositis, reduced pro-inflammatory cytokine expression, increased villus length, good maintenance of proliferative indices of villus cells, decreased apoptotic index of enterocytes, reduced gut permeability, and restoration of tight junction protein expression (vs. 5-FU-treated wild-type mice). Under in vitro conditions, siRNA-mediated SPAK-knockdown in IEC-6 cells decreased cell permeability and maintained homeostasis following 5-FU treatment.

Conclusion

SPAK deficiency attenuated chemotherapy-induced intestinal mucositis by modulating gut permeability and tight junction-associated protein expression and maintaining gut homeostasis in murine small intestinal tissues following gut injury. The expression of SPAK may influence the pathogenesis of chemotherapy-induced intestinal mucositis.

Blood microbiome is associated with changes in portal hypertension after successful direct-acting antiviral therapy in patients with HCV-related cirrhosis

BACKGROUND

Patients with a significant decrease in hepatic venous pressure gradient (HVPG) have a considerable reduction of liver complications and higher survival after HCV eradication.

OBJECTIVES

To evaluate the association between the baseline blood microbiome and the changes in HVPG after successful direct-acting antiviral (DAA) therapy in patients with HCV-related cirrhosis.

METHODS

We performed a prospective study in 32 cirrhotic patients (21 HIV positive) with clinically significant portal hypertension (HVPG ≥10 mmHg). Patients were assessed at baseline and 48 weeks after HCV treatment completion. The clinical endpoint was a decrease in HVPG of ≥20% or HVPG <12 mmHg at the end of follow-up. Bacterial 16S ribosomal DNA was sequenced using MiSeq Illumina technology, inflammatory plasma biomarkers were investigated using ProcartaPlex immunoassays and the metabolome was investigated using GC-MS.

RESULTS

During the follow-up, 47% of patients reached the clinical endpoint. At baseline, those patients had a higher relative abundance of Corynebacteriales and Diplorickettsiales order, Diplorickettsiaceae family, Corynebacterium and Aquicella genus and Undibacterium parvum species organisms and a lower relative abundance of Oceanospirillales and Rhodospirillales order, Halomonadaceae family and Massilia genus organisms compared with those who did not achieve the clinical endpoint according to the LEfSe algorithm. Corynebacteriales and Massilia were consistently found within the 10 bacterial taxa with the highest differential abundance between groups. Additionally, the relative abundance of the Corynebacteriales order was inversely correlated with IFN-γ, IL-17A and TNF-α levels and the Massilia genus with glycerol and lauric acid.

CONCLUSIONS

Baseline-specific bacterial taxa are related to an HVPG decrease in patients with HCV-related cirrhosis after successful DAA therapy.

Translocating lipopolysaccharide correlates with the severity of enterovirus A71-induced HFMD by promoting pro-inflammation and viral IRES activity

Background

The increase of inflammation-inducing enterobacteria was recently observed in severe hand, foot, and mouth disease (HFMD) caused by Enterovirus A71 (EV-A71). This study aimed to verify the occurrence of bacterial translocation (BT) and further explore the contributory role of BT to severity of EV-A71-mediated HFMD cases.

Methods

Serum specimens from 65 mild and 65 severe EV-A71-associated HFMD cases and 65 healthy children were collected. EV-A71 VP1 in serum, inflammatory mediators including C-reactive protein, IL-1β, IL-6, interferon-γ and tumor necrosis factor-α, BT related biomarkers including Claudin-3, intestinal fatty acid binding protein, lipopolysaccharide (LPS), soluble CD14 (sCD14) and endotoxin core antibody were measured by ELISA. Bacterial DNA (BactDNA) fragments were quantified by quantified PCR (qPCR). Rhabdomyosarcoma (RD) or SH-SY5Y cells, infected with LPS-pre-incubated EV-A71 or transfected with plasmid containing viral 2A^pro or mRNA containing viral internal ribosomal entry site (IRES), were post-treated with or without LPS in vitro. EV-A71 RNA and viral or cellular proteins were determined by qPCR and western blot, respectively.

Results

Compared to mild HFMD patients, remarkably higher inflammatory mediators as well as BT-related biomarkers except BactDNA were observed in severe HFMD cases (all P < 0.05). In severe HFMD group, circulating concentrations of LPS and sCD14 showed statistical correlations with inflammation indices (all P < 0.05), serum levels of EV-A71 VP1 were found to be positively correlated with serum LPS (r = 0.341, P = 0.005) and serum sCD14 (r = 0.458, P < 0.001). In vitro, EV-A71 attachment and internalization were only slightly promoted by LPS pre-incubation; however, EV-A71 proliferation and viral 2A^pro-mediated IRES activity were significantly accelerated by LPS post-treatment.

Conclusions

Our results collectively indicate that gut-derived translocating LPS contributes to the severity of EV-A71-induced HFMD by driving inflammatory response and viral proliferation via viral 2A^pro-mediated IRES.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13099-021-00465-x.

Overview of the microbiota in the gut-liver axis in viral B and C hepatitis

Viral B and C hepatitis are a major current health issue, both diseases having a chronic damaging effect on the liver and its functions. Chronic liver disease can lead to even more severe and life-threatening conditions, such as liver cirrhosis and hepatocellular carcinoma. Recent years have uncovered an important interplay between the liver and the gut microbiome: the gut-liver axis. Hepatitis B and C infections often cause alterations in the gut microbiota by lowering the levels of ‘protective’ gut microorganisms and, by doing so, hinder the microbiota ability to boost the immune response. Treatments aimed at restoring the gut microbiota balance may provide a valuable addition to current practice therapies and may help limit the chronic changes observed in the liver of hepatitis B and C patients. This review aims to summarize the current knowledge on the anato-functional axis between the gut and liver and to highlight the influence that hepatitis B and C viruses have on the microbiota balance, as well as the influence of treatments aimed at restoring the gut microbiota on infected livers and disease progression.

Gut microbiota as prognosis markers for patients with HBV-related acute-on-chronic liver failure

The gut microbiota in the hepatitis B virus related acute-on-chronic liver failure (HBV-ACLF) is poorly defined. We aim to uncover the characteristics of the gut microbiota in HBV-ACLF and in other HBV associated pathologies. We analyzed the gut microbiome in patients with HBV-ACLF or other HBV associated pathologies and healthy individuals by 16S rRNA sequencing and metagenomic sequencing of fecal samples. 212 patients with HBV-ACLF, 252 with chronic hepatitis B (CHB), 162 with HBV-associated cirrhosis (HBV-LC) and 877 healthy individuals were recruited for the study. CHB and HBV-LC patients are grouped as HBV-Other. We discovered striking differences in the microbiome diversity between the HBV-ACLF, HBV-Other and healthy groups using 16S rRNA sequencing. The ratio of cocci to bacilli was significantly elevated in the HBV-ACLF group compared with healthy group. Further analysis within the HBV-ACLF group identified 52 genera showing distinct richness within the group where Enterococcus was enriched in the progression group whilst Faecalibacterium was enriched in the regression group. Metagenomic sequencing validated these findings and further uncovered an enrichment of Lactobacillus casei paracasei in progression group, while Alistipes senegalensis, Faecalibacterium prausnitzii and Parabacteroides merdae dominated the regression group. Importantly, our analysis revealed that there was a rapid increase of Enterococcus faecium during the progression of HBV-ACLF. The gut microbiota displayed distinct composition at different phases of HBV-ACLF. High abundance of Enterococcus is associated with progression while that of Faecalibacterium is associated with regression of HBV-ACLF. Therefore, the microbiota features hold promising potential as prognostic markers for HBV-ACLF.

Diagnostic Utility of Presepsin in Infections After Liver Transplantation: A Preliminary Study

BACKGROUND Infectious complications after solid organ transplantation can be fatal, and early diagnosis and intervention are important. To the best of our knowledge, no study has examined the diagnostic utility of presepsin, a known accurate biomarker, for infectious complications after liver transplantation. This study aimed to evaluate the utility of presepsin for detecting infection and perioperative kinetics of presepsin after liver transplantation. MATERIAL AND METHODS This single-institutional prospective, observational study included 13 patients who underwent living-donor or deceased-donor liver transplantation. Perioperative serum presepsin level was measured 6 times within a week to evaluate its association with infectious complications and compare it with procalcitonin and C-reactive protein levels and leukocyte count. Postoperatively, patients were followed up for 15 days for infectious complications. RESULTS Five of the 13 patients developed infectious complications after liver transplantation. The median time for infection diagnosis was 9 postoperative days (25th-75th percentile, 7-10). Presepsin levels on 5 and 7 postoperative days were significantly higher in patients with infection than in those without (P=0.019 and P=0.011, respectively). In receiver operating characteristic analysis, area under the curve values of presepsin on 5 and 7 postoperative days (0.881 and 0.905, respectively) were higher than those of other biomarkers. The optimal cut-off value of presepsin was 1361 pg/mL on postoperative day 5 and 1375 pg/mL on postoperative day 7. CONCLUSIONS Although this study included a small number of patients, presepsin levels on postoperative days 5 and 7 may be useful indicators for infectious complications after liver transplantation.

Microbial Translocation in the Context of Hepatitis B Infection and Hepatitis D Infection

BACKGROUND

Increased microbial translocation (MT) into the systemic circulation is associated with liver disease progression. Microbial translocation has yet to be completely defined in chronic hepatitis B virus (HBV) and chronic hepatitis delta virus (HDV).

METHODS

Our aim was to characterize MT and associated immune response in chronic HBV and HDV at various stages of disease. Serum from 53 HBV, 43 HDV, and 36 healthy control (HC) subjects was obtained. Subjects were categorized by aspartate aminotransferase-to-platelet ratio index into mild (<0.5), moderate, and severe (>1.0) disease. Cytokines, microbial products, and microbial deoxyribonucleic acid (DNA) levels were assessed in a single treatment-naive time point for each patient. Next-generation sequencing identified bacterial species present within patient sera.

RESULTS

The HBV and HDV subjects display higher serum concentrations of Gram-negative (G-) bacterial lipopolysaccharide and fungal beta-glucan compared with HC (all P < .01). Gram-positive (G+) bacterial peptidoglycan is higher in HBV compared to HDV and HC (both P < .0001). Within both disease cohorts, peptidoglycan correlates with interleukin (IL)-1b, IL-8, IL-12p70, and IL-13 (all Spearman's rho >0.45; P < .05). Next-generation sequencing from 7 subjects with detectable serum bacterial DNA revealed changes in abundance of bacterial taxa and a higher proportion of Gram-positive genera in severe disease. Greater G+/G- taxa ratio is associated with higher cytokine levels and disease markers.

CONCLUSIONS

The HBV and HDV patients display increased translocation of bacterial and fungal products into serum. An increased proportion of Gram-positive genera is associated with disease progression. Correlations of peptidoglycan with antimicrobial cytokines suggest that particular microbial classes may contribute to systemic inflammation and possibly disease progression.

Persistent chronic immune activation in HIV/HBV-coinfected patients after antiretroviral therapy

We studied the characteristics of immune activation and investigated the underlying mechanisms in patients with human immunodeficiency virus-1/hepatitis B virus (HIV/HBV) coinfection after receiving HBV-active antiretroviral therapy. Forty patients with HIV/HBV coinfection, 38 patients with HIV monoinfection and 20 healthy controls were enrolled. CD4⁺ count, HIV load, HBV load, markers of immune activation and regulatory T-cell (Treg cell) frequency were assessed and compared between HIV-monoinfected and HIV/HBV-coinfected patients at week 0 (baseline), 12, 24, 36 and 48 after the onset of HBV-active antiretroviral therapy. Before antiretroviral therapy, frequencies of CD4⁺ HLADR⁺ CD38⁺ , CD8⁺ HLADR⁺ CD38⁺ , and Treg cells, and sCD163 and sCD14 levels were significantly higher in both HIV/HBV-coinfected patients and HIV-monoinfected patients, compared with healthy controls. Frequencies of CD4⁺ HLADR⁺ CD38⁺ and CD8⁺ HLADR⁺ CD38⁺ cells decreased following antiretroviral therapy in both groups. sCD163 levels did not change significantly in both groups and no significant difference was observed between the two groups at each time point during the 48-week antiretroviral therapy. In week 24, levels of sCD14 and frequencies of Treg cells appeared significantly higher in HIV/HBV-coinfected patients than in HIV-monoinfected patients, in which sCD14 levels and Treg cell frequencies declined to those in healthy controls. The Treg cell frequency was consistent with that of sCD14 levels in HIV/HBV-coinfected patients. Coinfection with HBV significantly increases sCD14 levels in HIV-infected patients during HBV-active antiretroviral therapy, which may potentially contribute to liver inflammation.

The use of biomarkers associated with leaky gut as a diagnostic tool for early intervention in autism spectrum disorder: a systematic review

Background

Innovative research highlighted the probable connection between autism spectrum disorder (ASD) and gut microbiota as many autistic individuals have gastrointestinal problems as co-morbidities. This review emphasizes the role of altered gut microbiota observed frequently in autistic patients, and the mechanisms through which such alterations may trigger leaky gut.

Main body

Different bacterial metabolite levels in the blood and urine of autistic children, such as short-chain fatty acids, lipopolysaccharides, beta-cresol, and bacterial toxins, were reviewed. Moreover, the importance of selected proteins, among which are calprotectin, zonulin, and lysozyme, were discussed as biomarkers for the early detection of leaky gut as an etiological mechanism of ASD through the less integrative gut–blood–brain barriers. Disrupted gut–blood–brain barriers can explain the leakage of bacterial metabolites in these patients.

Conclusion

Although the cause-to-effect relationship between ASD and altered gut microbiota is not yet well understood, this review shows that with the consumption of specific diets, definite probiotics may represent a noninvasive tool to reestablish healthy gut microbiota and stimulate gut health. The diagnostic and therapeutic value of intestinal proteins and bacterial-derived compounds as new possible biomarkers, as well as potential therapeutic targets, are discussed.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13099-021-00448-y.

Markers of Monocyte Activation, Inflammation, and Microbial Translocation Are Associated with Liver Fibrosis in Alcohol Use Disorder

BACKGROUND

The association between markers of inflammation (interleukin (IL)-6 and IL-10), monocyte activation (sCD163 and sCD14), and microbial translocation (lipopolysaccharide (LPS) and LPS binding protein) and liver fibrosis in patients with alcohol use disorder (AUD) and no overt liver disease is not well established.

METHODS

We studied patients admitted for treatment of AUD at two hospitals in Barcelona. Advanced liver fibrosis (ALF) was defined as FIB-4 > 3.25.

RESULTS

A total of 353 participants (76.3% male) were included and 94 (26.5%) had ALF. In adjusted correlation analyses, sCD163, sCD14, IL-6, IL-10, and LPS binding protein levels directly correlated with FIB-4 values (adjusted correlation coefficients 0.214, 0.452, 0.317, 0.204, and 0.171, respectively). However, LPS levels were inversely associated with FIB-4 (-0.283). All plasma marker levels in the highest quartile, except LPS, were associated with ALF (sCD163, sCD14, IL-6, IL-10, and LPS binding protein: adjusted odds ratio (aOR) 11.49 (95% confidence interval 6.42-20.56), 1.87 (1.11-3.16), 2.99 (1.79-5.01), 1.84 (1.11-3.16), and 2.13 (1.30-3.50), respectively). Conversely, LPS levels in the lowest quartile were associated with ALF (aOR 2.58 (1.48-4.58), p < 0.01).

CONCLUSION

In AUD patients, plasma levels of the markers of inflammation, monocyte activation, and microbial translocation are associated with ALF.

Liver Injury and the Macrophage Issue: Molecular and Mechanistic Facts and Their Clinical Relevance

The liver is an essential immunological organ due to its gatekeeper position to bypassing antigens from the intestinal blood flow and microbial products from the intestinal commensals. The tissue-resident liver macrophages, termed Kupffer cells, represent key phagocytes that closely interact with local parenchymal, interstitial and other immunological cells in the liver to maintain homeostasis and tolerance against harmless antigens. Upon liver injury, the pool of hepatic macrophages expands dramatically by infiltrating bone marrow-/monocyte-derived macrophages. The interplay of the injured microenvironment and altered macrophage pool skews the subsequent course of liver injuries. It may range from complete recovery to chronic inflammation, fibrosis, cirrhosis and eventually hepatocellular cancer. This review summarizes current knowledge on the classification and role of hepatic macrophages in the healthy and injured liver.

Soluble cluster of differentiation 14 levels elevated in bile from gallbladder cancer cases from Shanghai, China

Elevated systemic levels of soluble cluster of differentiation 14 (sCD14) have been associated with gallbladder cancer (GBC), but the association with sCD14 levels within the gallbladder has not been investigated. Here, we evaluated sCD14 in the bile of 41 GBC cases and 117 gallstone controls with data on 65 bile inflammation markers. We examined the relationship between bile sCD14 levels and GBC using logistic regression and stratified the analysis by stage. We included GBC-associated inflammatory biomarkers in the model to evaluate the influence of local inflammation. Bile sCD14 levels (third versus first tertile) were associated with GBC (adjusted odds ratio [OR]: 3.0, 95% confidence interval [CI]: 1.2–8.0). The association was equally strong for stage I/II (OR: 3.3, 95% CI: 0.9–15.6) and stage III/IV (OR: 3.2, 95% CI: 1.0–12.4) cancers. Including the GBC-associated inflammatory markers in the model removed the association between bile sCD14 and GBC (OR: 1.0, 95% CI: 0.3–3.5). The findings suggest that immune activation within the gallbladder may be related to GBC development, and the effect of sCD14 is influenced by inflammation. Similar associations across tumor stages suggest that elevated bile sCD14 levels may reflect changes early in GBC pathogenesis. Associations between GBC and sCD14 levels in both bile and plasma suggest sCD14 could be a potential biomarker for GBC.

Impact of the Gut Microbiome on the Progression of Hepatitis B Virus Related Acute-on-Chronic Liver Failure

The relationship between the progression of hepatitis B virus-related acute-on-chronic liver failure (HBV-ACLF) and the gut microbiota is poorly understood, and an HBV-ACLF-related microbiome has yet to be identified. In this study alterations in the fecal microbiome of 91 patients with HBV-ACLF (109 stool samples), including a cohort of nine patients at different stages of HBV-ACLF, were determined by high-throughput 16S rDNA sequencing. The operational taxonomic units and Shannon indexes indicated that the diversity and abundance of the gut microbiome significantly decreased with the progression of HBV-ACLF (p <0.05). The relative abundance of the Bacteroidetes phylum in the microbiome was significantly reduced, whereas the abundance of potentially pathogenic bacteria, such as Veilonella, Streptococcus, Enterococcus, and Klebsiella, was highly enriched in the HBV-ACLF group compared with the healthy control group. The abundance of Bacteroidetes was negatively correlated with the level of serum alpha fetoprotein, and the abundance of Veilonella was positively correlated with serum total bilirubin (TBIL). Furthermore, the abundance of Coprococcus was significantly negatively correlated with the level of serum TBIL and the international normalized ratio and positively correlated with prothrombin time activity. Our findings suggest that the gut microbiota plays an important role in the development of HBV-ACLF.

Macrophages in Chronic Liver Failure: Diversity, Plasticity and Therapeutic Targeting

Chronic liver injury results in immune-driven progressive fibrosis, with risk of cirrhosis development and impact on morbidity and mortality. Persistent liver cell damage and death causes immune cell activation and inflammation. Patients with advanced cirrhosis additionally experience pathological bacterial translocation, exposure to microbial products and chronic engagement of the immune system. Bacterial infections have a high incidence in cirrhosis, with spontaneous bacterial peritonitis being the most common, while the subsequent systemic inflammation, organ failure and immune dysregulation increase the mortality risk. Tissue-resident and recruited macrophages play a central part in the development of inflammation and fibrosis progression. In the liver, adipose tissue, peritoneum and intestines, diverse macrophage populations exhibit great phenotypic and functional plasticity determined by their ontogeny, epigenetic programming and local microenvironment. These changes can, at different times, promote or ameliorate disease states and therefore represent potential targets for macrophage-directed therapies. In this review, we discuss the evidence for macrophage phenotypic and functional alterations in tissue compartments during the development and progression of chronic liver failure in different aetiologies and highlight the potential of macrophage modulation as a therapeutic strategy for liver disease.

Hepatitis C Virus (HCV) Direct-Acting Antiviral Therapy in Persons With Human Immunodeficiency Virus-HCV Genotype 1 Coinfection Resulting in High Rate of Sustained Virologic Response and Variable in Normalization of Soluble Markers of Immune Activation

BACKGROUND

Hepatitis C virus (HCV) direct-acting antivirals are highly effective. Less is known about changes in markers of immune activation in persons with human immunodeficiency virus (HIV) in whom a sustained virologic response (SVR) is achieved.

METHODS

We conducted a nonrandomized clinical trial of 12 or 24 weeks of paritaprevir-ritonavir-ombitasvir plus dasabuvir (PrOD) with or without ribavirin in persons with HCV-1/HIV coinfection suppressed with antiretroviral therapy. Plasma HCV, soluble CD14 (sCD14), interferon-inducible protein 10, soluble CD163 (sCD163), interleukin 6 (IL-6), interleukin 18, monocyte chemoattractant protein (MCP-1), autotaxin (ATX), and Mac2-binding protein (Mac2BP) were measured over 48 weeks.

RESULTS

Participants were treated with PrOD for 12 (n = 9) or 24 (n = 36) weeks; the SVR rate at 12 weeks was 93%. At baseline, cirrhosis was associated with higher ATX and MCP-1, female sex with higher ATX and IL-6, older age with higher Mac2BP, higher body mass index with higher ATX, and HIV-1 protease inhibitor use with higher sCD14 levels. In those with SVR, interferon-inducible protein 10, ATX, and Mac2BP levels declined by week 2, interleukin 18 levels declined by the end of treatment, sCD14 levels did not change, and sCD163, MCP-1, and IL-6 levels changed at a single time point.

CONCLUSIONS

During HIV/HCV coinfection, plasma immune activation marker heterogeneity is in part attributable to age, sex, cirrhosis, body mass index, and/or type of antiretroviral therapy. HCV treatment with paritaprevir-ritonavir-ombitasvir plus dasabuvir is highly effective and is associated with variable rate and magnitude of decline in markers of immune activation.

CLINICAL TRIALS REGISTRATION

NCT02194998.

Improvement of Gut Diversity and Composition after Direct-Acting Antivirals in HCV-Infected Patients with or without HIV Coinfection

BACKGROUND

The influence of direct-acting antivirals (DAAs) on the composition of gut microbiota in hepatitis C virus (HCV)-infected patients with or without human immunodeficiency virus (HIV) is unclear.

METHODS

We enrolled 62 patients with HCV monoinfection and 24 patients with HCV/HIV coinfection receiving elbasvir/grazoprevir from a clinical trial. Fecal specimens collected at pre-treatment and 12 weeks post-treatment were analyzed using amplicon-based 16S rRNA sequencing.

RESULTS

Sustained virological response (SVR12) rates in the mono- and co-infection groups were similar (98.4%vs.95.8%). Pre-treatment bacterial communities in the patient groups were less diverse and distinct from those of healthy controls. Compared with HCV-monoinfected patients, HCV/HIV-coinfected individuals showed comparable microbial alpha-diversity but displayed declined Firmicutes/Bacteroidetes ratio. The improvement of microbial dysbiosis was observed in responders achieving SVR12 across fibrosis stages but was not found in non-responders. Responders with low degree of fibrosis exhibited a recovery in alpha-diversity to level comparable with healthy controls. Reciprocal alterations of increased beneficial bacteria and reduced pathogenic bacteria were also observed in responders.

CONCLUSIONS

This study indicates short-term effect of DAAs in restoration of microbial dysbiosis. The favorable changes in gut microbiota profiles after viral eradication might potentially contribute towards the reduction of HCV-related complications among infected individuals.

Macrophage Phenotypes and Hepatitis B Virus Infection

Globally, hepatitis B virus (HBV) infection and its related liver diseases account for 780,000 deaths every year. Outcomes of HBV infection depend on the interaction between the virus and host immune system. It is becoming increasingly apparent that Kupffer cells (KCs), the largest population of resident and monocyte-derived macrophages in the liver, contribute to HBV infection in various aspects. These cells play an important role not only in the anti-HBV immunity including virus recognition, cytokine production to directly inhibit viral replication and recruitment and activation of other immune cells involved in virus clearance but also in HBV outcome and progression, such as persistent infection and development of end-stage liver diseases. Since liver macrophages play multiple roles in HBV infection, they are directly targeted by HBV to benefit its life cycle. In the present review, we briefly outline the current advances of research of macrophages, especially the studies of their phenotypes, in chronic HBV infection.

Gut Microbiota, Peroxisome Proliferator-Activated Receptors, and Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors in the world. HCC incidence rate is sixth and mortality is fourth worldwide. However, HCC pathogenesis and molecular mechanisms remain unclear. The incidence of HCC is associated with genetic, environmental, and metabolic factors. The role of gut microbiota in the pathogenesis of HCC has attracted researchers’ attention because of anatomical and functional interactions between liver and intestine. Studies have demonstrated the involvement of gut microbiota in the development of HCC and chronic liver diseases, such as alcoholic liver disease (ALD), nonalcoholic fatty liver disease (NAFLD), and liver cirrhosis. Peroxisome proliferator-activated receptors (PPARs) are a group of receptors with diverse biological functions. Natural and synthetic PPAR agonists show potential for treatment of NAFLD, liver fibrosis, and HCC. Recent studies have demonstrated that PPARs take part in gut microbiota inhabitation and adaptation. This manuscript reviews the role of gut microbiota in the development of HCC and precancerous diseases, the role of PPARs in modulation of gut microbiota and HCC, and potential of gut microbiota for HCC diagnosis and treatment.

Intestinal permeability and bacterial translocation in patients with liver disease, focusing on alcoholic aetiology: methods of assessment and therapeutic intervention

Increased bacterial translocation (BT) across the gut barrier due to greater intestinal permeability (IP) is seen across a range of conditions, including alcohol-related liver disease (ArLD). The phenomenon of BT may contribute to both the pathogenesis and the development of complications in ArLD. There are a number of methods available to assess IP and in this review we look at their various advantages and limitations. The knowledge around BT and IP in ArLD is also reviewed, as well as the therapeutic strategies currently in use and in development.

Abnormal Innate Immunity in Acute-on-Chronic Liver Failure: Immunotargets for Therapeutics

Acute-on-chronic liver failure (ACLF) is a severe life-threatening condition with high risk of multiorgan failure, sepsis, and mortality. ACLF activates a multifaceted interplay of both innate and adaptive immune response in the host which governs the overall outcome. Innate immune cells recognize the conserved elements of microbial and viral origin, both to extort instant defense by transforming into diverse modules of effector responses and to generate long-lasting immunity but can also trigger a massive intrahepatic immune inflammatory response. Acute insult results in the activation of innate immune cells which provokes cytokine and chemokine cascade and subsequently initiates aggressive systemic inflammatory response syndrome, hepatic damage, and high mortality in ACLF. Dysregulated innate immune response not only plays a critical role in disease progression but also potentially correlates with clinical disease severity indices including Child-Turcotte-Pugh, a model for end-stage liver disease, and sequential organ failure assessment score. A better understanding of the pathophysiological basis of the disease and precise immune mechanisms associated with liver injury offers a novel approach for the development of new and efficient therapies to treat this severely ill entity. Immunotherapies could be helpful in targeting immune-mediated organ damage which may constrain progression toward liver failure and eventually reduce the requirement for liver transplantation. Here, in this review we discuss the defects of different innate immune cells in ACLF which updates the current knowledge of innate immune response and provide potential targets for new therapeutic interventions.

Gut-Pancreas-Liver Axis as a Target for Treatment of NAFLD/NASH

Non-alcoholic fatty liver disease (NAFLD) represents the most common form of chronic liver disease worldwide. Due to its association with obesity and diabetes and the fall in hepatitis C virus morbidity, cirrhosis in NAFLD is becoming the most frequent indication to liver transplantation, but the pathogenetic mechanisms are still not completely understood. The so-called gut-liver axis has gained enormous interest when data showed that its alteration can lead to NAFLD development and might favor the occurrence of non-alcoholic steatohepatitis (NASH). Moreover, several therapeutic approaches targeting the gut-pancreas-liver axis, e.g., incretins, showed promising results in NASH treatment. In this review, we describe the role of incretin hormones in NAFLD/NASH pathogenesis and treatment and how metagenomic/metabolomic alterations in the gut microbiota can lead to NASH in the presence of gut barrier modifications favoring the passage of bacteria or bacterial products in the portal circulation, i.e., bacterial translocation.

Innate Immune Response against Hepatitis C Virus: Targets for Vaccine Adjuvants

Despite successful treatments, hepatitis C virus (HCV) infections continue to be a significant world health problem. High treatment costs, the high number of undiagnosed individuals, and the difficulty to access to treatment, particularly in marginalized susceptible populations, make it improbable to achieve the global control of the virus in the absence of an effective preventive vaccine. Current vaccine development is mostly focused on weakly immunogenic subunits, such as surface glycoproteins or non-structural proteins, in the case of HCV. Adjuvants are critical components of vaccine formulations that increase immunogenic performance. As we learn more information about how adjuvants work, it is becoming clear that proper stimulation of innate immunity is crucial to achieving a successful immunization. Several hepatic cell types participate in the early innate immune response and the subsequent inflammation and activation of the adaptive response, principally hepatocytes, and antigen-presenting cells (Kupffer cells, and dendritic cells). Innate pattern recognition receptors on these cells, mainly toll-like receptors, are targets for new promising adjuvants. Moreover, complex adjuvants that stimulate different components of the innate immunity are showing encouraging results and are being incorporated in current vaccines. Recent studies on HCV-vaccine adjuvants have shown that the induction of a strong T- and B-cell immune response might be enhanced by choosing the right adjuvant.

LPS stimulation during HCV infection induces MMP/TIMP1 imbalance in macrophages

Introduction. During chronic hepatitis C virus (HCV) infections, HCV antigens establish cross-tolerance of endotoxins, but additional lipopolysaccharide (LPS) stimulation effects in this condition are poorly understood.Aim. This study aims to investigate the effects of the upregulated LPS on MMP and TIMP expression during chronic hepatitis C infection.Methodology. In the present study, we analysed the effect of HCV antigens and LPS stimulation on peripheral blood mononuclear cells (PBMCs) both in vivo and in vitro. Macrophages from HCV patients were isolated and their association with endotoxin tolerance was examined. MMP/TIMP1 expression and the related signalling pathways in macrophages were analysed. The macrophage and Huh7.5 cell co-culture model was used to analyse the effects of the cross-tolerance on collagen I deposition.Results. LPS levels were found to be significantly higher in HCV patients, particularly in those with HCV-induced liver fibrosis. In addition, although LPS serum level was occasionally upregulated in the patients, it did not induce intense immune response in PBMCs due to endotoxin cross-tolerance, and this was measured according to the changes in IL-6 and TNF-α levels. However, TIMP1 expression increased significantly during stimulation, exhibiting a tolerance/resistance phenotype, which was associated with TGF-β/Erk activation in macrophages. However, MMP levels did not increase due to endotoxin tolerance, which ultimately led to MMP/TIMP imbalance and influenced the deposition of collagen I.Conclusion. Increased LPS stimulation of macrophage during HCV antigen-induced endotoxin cross-tolerance contributes to MMP/TIMP1 imbalance and collagen I deposition.

The Candida albicans exotoxin candidalysin promotes alcohol-associated liver disease

BACKGROUND & AIMS

Alcohol-associated liver disease is a leading indication for liver transplantation and a leading cause of mortality. Alterations to the gut microbiota contribute to the pathogenesis of alcohol-associated liver disease. Patients with alcohol-associated liver disease have increased proportions of Candida spp. in the fecal mycobiome, yet little is known about the effect of intestinal Candida on the disease. Herein, we evaluated the contributions of Candida albicans and its exotoxin candidalysin in alcohol-associated liver disease.

METHODS

C. albicans and the extent of cell elongation 1 (ECE1) were analyzed in fecal samples from controls, patients with alcohol use disorder and those with alcoholic hepatitis. Mice colonized with different and genetically manipulated C. albicans strains were subjected to the chronic-plus-binge ethanol diet model. Primary hepatocytes were isolated and incubated with candidalysin.

RESULTS

The percentages of individuals carrying ECE1 were 0%, 4.76% and 30.77% in non-alcoholic controls, patients with alcohol use disorder and patients with alcoholic hepatitis, respectively. Candidalysin exacerbates ethanol-induced liver disease and is associated with increased mortality in mice. Candidalysin enhances ethanol-induced liver disease independently of the β-glucan receptor C-type lectin domain family 7 member A (CLEC7A) on bone marrow-derived cells, and candidalysin does not alter gut barrier function. Candidalysin can damage primary hepatocytes in a dose-dependent manner in vitro and is associated with liver disease severity and mortality in patients with alcoholic hepatitis.

CONCLUSIONS

Candidalysin is associated with the progression of ethanol-induced liver disease in preclinical models and worse clinical outcomes in patients with alcoholic hepatitis.

LAY SUMMARY

Candidalysin is a peptide toxin secreted by the commensal gut fungus Candida albicans. Candidalysin enhances alcohol-associated liver disease independently of the β-glucan receptor CLEC7A on bone marrow-derived cells in mice without affecting intestinal permeability. Candidalysin is cytotoxic to primary hepatocytes, indicating a direct role of candidalysin on ethanol-induced liver disease. Candidalysin might be an effective target for therapy in patients with alcohol-associated liver disease.